The present invention relates to a method of coating geological formations, as well as air- and fire barriers.
It is known that under the action of water, for example in form of moist air, the strength of clay-containing minerals considerably decreases, which can lead to complete disintegration. In rocks which have a tendency to swell, this process progresses in certain conditions very fast. Particularly in mine and tunnel construction, the water content of such rocks from the outer surface increases very fast, because of high air moisture in the environment, and thereby the moisture of the rock is increased. This is shown, for example, in peeling of rock layers, in stoning, in swelling of the sole and generally in a stronger convergence of the rock, while simultaneously rock movement and pressure are increased. In the event of pillar-and-chamber work in coal mining, this can lead to the situation in which one must excavate top coal in a roof of approximately 30 cm to prevent a collapse of the gallery. By placing a water-impermeable coating layer, the rock susceptible to quelling can be preserved, and a complete excavation of the stratum is made possible.
In underground works, the galleries must frequently be sealed against gaseous air streams. Such streams lead, first of all, in abandoned mine structures to smoldering fires. For preventing this, fire-protective barriers are erected to protect the potential fire zones from an additional oxygen supply. Air barriers are erected to guarantee an exact and effective air supply required for those working at front locations. In general, for this purpose the air- or fire-protective barriers are composed of wood or mineral material. These materials, however, have considerable untightness, first of all in the transition regions barrier-joint and barrier-roof. The air losses are increased by loosening and therefore air-permeability of the adjoining rock. The leakages in the barrier are conventionally sealed by urea formaldehyde foam. During rock movement, small cracks can, however, generate in the coating, particularly in the event of utilization of mortar, so that the barrier is no longer tight. Similarly, during pillar-and-chamber work, high air losses take place because the coal of the field to be evacuated is air-permeable toward the adjoining field.
German patent No. 1,082,876 discloses a method of sealing air- or fire barriers by simultaneous spraying of a latex dispersion and a filling medium. Thereby an air- and liquid-tight film is applied. The fire-resistance of this film is, however, not satisfactory.